Electric sparking plug.



Patented Nov. 26, 190i.

L C URSWELL.

ELECTRIC SPARKING PLUG.

(Application filed Jan. 3, 1901) (No Model.)

THE Norms PEYERS co. PHOTD-LITNEL. \vnsnmm'on. I: c.

UNITED STATES PATENT OFFICE.

ISRAEL 0. ORSWELL, OF OAMBRIDGEPORT, MASSACHUSETTS.

ELECTRIC SPARKQING PLUG.

SPECIFICATION forming part Of Letters Patent No. 687,648, dated November26, 1901.

Application filed January 3, 1901- Serial No. 41,992. (No model.)

To all whom it nut/y concern.-

in which I Figure 1 is a section illustrating my improved plug asconnected to one of the walls of the explosion-chamber of an explosiveengine, and Fig. 2 comprises disconnected perspective views of the partsof which my improved plug is made up.

Referring by letter to the said drawings, A is awall of theexplosive-chamber of a gas or other explosive engine, the same beingprovided with a screw-tapped aperture a.

Bis a metallic sleeve having a threaded portion designed to occupy theaperture a and also having a taper bore.

0 is an electrode carried by and projecting from the inner end of thesleeve B at one side of the concavity c therein.

D is an exteriorly and interiorly tapered bushing preferably of mica,which is of about the proportional size illustrated, so as to snuglyoccupy the bore 1) of sleeve B and project above and below the same, asillustrated in Fig. 1.

E is a tapered rod which constitutes the other electrode of the plug andsnugly occupies the bore of bushingD and extends above and below thesame, as illustrated.

F Fare superposed disks, also preferably of mica, which surround thatportion of the bushing D which projects above the sleeve B.

G G are superposed disks, also preferably of mica, which surround theelectrode E and are disposed above the disks F.

H is a jam-nut arranged on the threaded upper portion of the rod orelectrode E and having for its purpose to clamp the mica disks againstthe sleeve B.

I is a binding-nut arranged above the jambetween the nuts H I andforming part of an electric circuit, in which the sleeve 13 is alsoarranged.

The meeting faces of the superposed mica disks F G are preferablyshellacked in order to exclude moisture.

Mica when employed as an insulating material is highly advantageous forthe reasons that it is not affected in any way by heat and moisture andalso because it is inexpensive and while very strongand durable issusceptible of being readily reduced to various forms. When applied inthe manner shown in Fig. 1 and hereinbefore described, the mica not onlyserves as insulation, but effects a perfectly gas-tight joint. Thislatter is due in large measure to the employment of the taper electrodeE in the taper bushing D and the snug arrangement of the latter in thetaper bore of the sleeve B, together with the interposition of the micadisks between the sleeve B and the jam-nut II, which latter iscalculated to crowd the disks down on the sleeve and draw the taperelectrode tightin the mica bushing D and the said mica bushing tight inthe taper bore of the metallic sleeve.

The concavity c in the inner end of the metallic sleeve 13 isadvantageous since it increases the distance between the end of thesleeve and the inner end of the electrode E and the portion of thebushing D between the sleeve and electrode, which contributes materiallyto the isolation of the electrode from the sleeve.

Notwithstanding the advantages it posseses it will be appreciated thatthe specific construction of the jump-spark plug shown and described isat once simple, compact, and strong.

Having described my invention, what I claim, and desire to secure byLetters Patent,

An electric sparking plug comprising a conductive sleeve having aconcave inner end, and also having a bore tapered or gradually reducedin diameter toward its outer end, an

electrode extending from the inner end of the sleeve at the side of theconcavity therein, a bushing of insulating material exteriorly taperedin conformity to and occupying the taper bore of the sleeve, and havinga bore tapered or gradually reduced in diameter toward its outer end;said bushing being extended beyond the inner and outer ends of thesleeve, an electrode tapered in conformity to and occupying the bore ofthe bushing and extending beyond the inner and outer ends thereof, andhaving its outer portion threaded, superposed disks of insulatingmaterial

